OBJECTIVES: 1. Culture of cells from febrile patients with leukemia and lymphoma, from both blood and tissue, to identify pyrogen-producing cells, and investigate the mechanism for their in vivo activation. 2. Study of human tumor cell lines, and viral-transformed mouse cells, to investigate EP production capacity in vitro. 3. Purification of rabbit EP, and investigation of its properties as well as its capacity to cause release of prostaglandins in vivo when applied to the rabbit hypothalamus. 4. Further investigation of the dynamics of EP formation and release in human and rabbit mononuclear phagocytes in various stages of differentiation. 5. Production and investigation of the properties of rabbit antibody to human EP. BIBLIOGRAPHIC REFERENCES: Bodel, P. and H. Miller. Pyrogen from mouse macrophages causes fever in mice. Proc. Soc. Exp. Biol. & Med. 151:93-96, 1976. Bodel, P. Colchicine stimulation of pyrogen production by human blood leukocytes. J. Exp. Med. 143: 1015-1026, 1976.